#define _CRT_SECURE_NO_WARNINGS 1
#include <iostream>
#include <vector>
#include <string>
using namespace std;

int main()
{
    string s1, s2;
    cin >> s1;
    cin >> s2;
    int n = s1.size(), m = s2.size();
    vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
    for (int i = 0;i <= m;i++) dp[0][i] = i;
    for (int i = 0;i <= n;i++) dp[i][0] = i;
    for (int i = 1;i <= n;i++)
    {
        for (int j = 1;j <= m;j++)
        {
            if (s1[i - 1] == s2[j - 1])
            {
                dp[i][j] = dp[i - 1][j - 1];
            }
            else
            {
                dp[i][j] = min(dp[i - 1][j], min(dp[i][j - 1], dp[i - 1][j - 1])) + 1;
            }
        }
    }
    cout << dp[n][m] << endl;
}
